Approximately 150,000 cases of colorectal cancer are diagnosed in the United States every year and one third of the patients will die from metastatic disease. The presence of many small (less than 3 mm) peritoneal (abdominal) tumor nodules from disseminated colorectal cancer is a surgical challenge. Therefore, we propose to use electrically conductive polymer nanoparticles to help identify and treat these small tumors by stimulating the particles to generate heat upon exposure to infrared light. Our goal is to understand how donor-acceptor electrically conductive polymer nanoparticles (ECPNs) can be used to target and treat colorectal micrometastases. We have recently developed water-soluble nanoparticles composed of a cyclopentadithiophene donor monomer co-polymerized with the 2,1,3- benzothiadiazole acceptor monomer to produce nano-PCPDTBT, which we have shown has significant capacity for absorbing infrared light to generate heat. As a next step, we propose to synthesize nano-PCPDTBT with functional groups to attach the nanoparticles to the surface of colorectal cancer cells. Photothermal ablation using f-nano-PCPDTBT could be easily employed during surgical debulking since the abdomen will already be open and the tissues available for individual infrared exposure. Many different classes of polymer nanoparticles are routinely used in medicine and we predict that donor-acceptor electrically conductive polymers represent a new group that could become well- accepted for hyperthermia as well as drug delivery, once they have been sufficiently evaluated. The proposed research is an opportunity to develop new materials and techniques to assist surgeons in the difficult task of identifying and removing colorectal cancer metastases during surgical debulking procedures, which will prolong patients' lives as well as reduce the tumor burden and hence the associated pain, thereby improving the patients' quality of life.